An enlarged thyroid gland is not necessarily due to iodine deficiency. Iodine deficiency is one of the causes of goiter. Abnormal thyroid function, thyroid adenoma and thyroid cancer may also cause goiter. 1. Goiter caused by iodine deficiency is mainly due to insufficient intake of iodine and compensatory hyperplasia of the thyroid gland, which is mainly seen in remote and iodine-deficient areas, and is now rare with the promotion of iodized salt consumption. 2. Abnormal thyroid function: hyperthyroidism and subacute thyroiditis may also lead to goiter. Hyperthyroidism can be manifested as diffuse enlargement of the thyroid gland and hyperthyroidism manifestations such as panic attacks, irritability, and lethargy. 3. Thyroid adenoma: thyroid adenoma often occurs on one side of the thyroid gland or both sides, with the enlargement of the tumor, the thyroid gland is also enlarged. Once found that the thyroid gland is enlarged, you should consult the doctor in time to avoid delaying the treatment.